Interrupted orbital motion in density-wave systems

TL;DR

This paper reveals that near the transition temperature, density-wave systems exhibit unusual orbital motion due to collective fluctuations, causing linear magnetoconductivity and potential instability, contrasting with conventional metallic behavior.

Contribution

It demonstrates how collective fluctuations near the transition temperature alter orbital motion and transport properties in density-wave systems, leading to novel magnetoconductivity effects.

Findings

Linear magnetoconductivity in weak magnetic fields

Sign change of conductivity at a critical magnetic field

Thermodynamic instability of the density-wave state

Abstract

In conventional metals, electronic transport in a magnetic field is characterized by the motion of electrons along orbits on the Fermi surface, which usually causes an increase in the resistivity through averaging over velocities. Here we show that large deviations from this behavior can arise in density-wave systems close to their ordering temperature. Specifically, enhanced scattering off collective fluctuations can lead to a change of direction of the orbital motion on reconstructed pockets. In weak magnetic fields, this leads to linear magnetoconductivity, the sign of which depends on the electric-field direction. At a critical magnetic field, the conductivity crosses zero for certain directions, signifying a thermodynamic instability of the density-wave state.